Question: Suppose the circumference of a circle is ${8\pi}$. What is its area?
Explanation: ${c = 8\pi}$ ${K = 16\pi}$ First, find the radius: $r = c/2\pi = {8\pi}/2\pi = {4}$ Now find the area: $K = \pi r^2$, so $K = \pi \cdot {4}^2 = {16\pi}$.